Vehicles include a power unit chamber, also referred to as an engine compartment, in a front portion. The power unit chamber includes, in addition to power units, such as an engine and a motor for travelling, a battery for supplying and receiving electric power to and from the travelling motor, an air cleaner for removing foreign matter from air to be supplied to the engine, and other devices. Patent Document 1, for example, discloses an arrangement structure in which an engine room (power unit chamber) includes an engine in substantially the center, an air cleaner in front of the engine, and a battery beside the engine.
Both the battery and the air cleaner need to be removed from the power unit chamber, as required, for maintenance such as inspection, repair, and replacement, for example. The frequency of maintenance is higher for the air cleaner than for the battery. It is therefore desirable to place the air cleaner in a position which is easier to access than a position of the battery. As the power unit chamber is typically accessed from the front of a vehicle, it is desirable to place the air cleaner in front of the battery in consideration of maintainability. In view of stability of a vehicle, it is desirable to dispose a heavy object, such as a battery, close to the center of a vehicle. Therefore, when the battery and the air cleaner are disposed adjacent to each other in the forward-rearward direction of a vehicle, it is desirable to dispose the battery further rearward in the vehicle than the air cleaner. When the battery and the air cleaner are disposed adjacently in the width direction of a vehicle, it is desirable to dispose the battery more inwardly than the air cleaner in the width direction of the vehicle. As such, to establish both vehicle stability and maintainability, it is desirable that the air cleaner and the battery are disposed adjacently such that the air cleaner is disposed further forward, or further outward in the vehicle width direction, and the battery is disposed further rearward or inward in the vehicle width direction.